This invention relates to a process for preparing granular food products and, more particularly, to a process for preparing granular food products having improved fluidity and solubility from at least one member selected from various food material powders represented by fragrant and pungent powders such as curry and pepper powders, cereal powders such as wheat flour and the like, and food material powders of fat and oil-containing foods represented by curry soup, stew, corn soup and potage soup.
As conventional processes for granulating food material powders, a varity of granulation processes such as fluid bed, extruding and spraying granulation processes have been known. These granulation processes have been generally referred to as the so-called wet granulation process and the wet granulation process requires hydrating, granulating and drying steps. That is, in the wet granulation process, it is required that after materials have been hydrated and then granulated, the moisture obtained in the granules evaporates. As a result, the wet process requires an additional step of drying granules. However, when the moisture in the granules is evaporated in the drying step, there is the disadvantage that the fragrant components also are volatized from the granules simultaneously with the vaporization of the moisture from the granules or the granules tend to become substantially hard due to moisture evaporation resulting in granules which do not promptly and easily dissolve in boiling water.
In order to eliminate the disadvantage, it has been found that the granulation process which does not require the hydrating step or the granulation and which is generally referred to as the dry granulation process is advantageous.
As the dry granulation process, the process in which fat and oil in a molten state are sprayed over food material powder to be granulated has been known. In the process it is required to melt fat and oil and then spray the fat and oil maintained in the molten state over the powder to be granulated and thus, the process has the disadvantages that special devices such as fat and oil heating and spray devices are required, that the sprayed fat and oil have to uniformly contact the powder to be granulated, that the uniform contact between the fat and oil and powder is in practice difficult and that the obtained granules tend to have a wide particle size distribution and as a result, particle size adjustment is difficult.
According to another known dry granulation process, binder having a high melting point such as a solid fat is previously heat-melted, powder to be granulated is added to the molten binder, the binder and powder are heated under agitation to prepare a mixture and the mixture is cooled. However, the dry process also has the disadvantage that uniform dispersion of the powder throughout the binder cannot be easily attained and as a result, the particle size distribution in the obtained granulated product becomes wider than that in the granulated product obtainable by the first-mentioned dry process to the degree tht the particle size adjustment is rendered difficult and in an extreme case, some portion of the powder remains ungranulated resulting in substantial diminution of granulation efficiency.